The invention relates to an accurate-positioning large stroke conveying device. The accurate-positioning large stroke conveying device is composed of a main supporting assembly, a walking assembly and a power driving assembly in a connected mode. The main supporting assembly comprises main installing frames, waking rails, guiding rails, backing-limiting-block installing bases, advancing-limiting-block installing bases, adjusting bolts, baseboards, backing limiting blocks A and advancing limiting blocks A; the walking assembly comprises walking wheels, walking-wheel installing plates, a rack, main walking supports, advancing limiting blocks B, guiding wheels, a guiding-wheel installing plate, backing-limiting-block supporting bases and backing limiting blocks B; the power driving assembly comprises a driving motor, transition supporting bases, adjusting blocks, gaskets, gears, a motor installing base, an expanding sleeve, a shaft, a hole elastic stopping ring, a bearing, a coupling A, a speed reducer A, a coupling B, a speed reducer B and a coupling C. In the limited space, the accurate-positioning large stroke conveying device can achieve large stroke conveying, the operating speed is high, operating is stable, the positioning accuracy is high, and the accurate-positioning large stroke conveying device can be widely applied to an automatic automobile welding line.